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• Alias Artifacts

  26 avril 2013, par Multimedia Mike — General

  Throughout my own life, I have often observed that my own sense of nostalgia has a window that stretches about 10-15 years past from the current moment. Earlier this year, I discovered the show “Alias” and watched through the entire series thanks to Amazon Prime Instant Video (to be fair, I sort of skimmed the fifth and final season which I found to be horribly dull, or maybe franchise fatigue had set in). The show originally aired from 2001-2006 so I found that it fit well within the aforementioned nostalgia window.

  
  
  

  But what was it, exactly, about the show that triggered nostalgia ? The computers, of course ! The show revolved around spies and espionage and cutting-edge technology necessarily played a role. The production designer for the series must have decided that Unix/Linux == awesome hacking and so many screenshots featured Linux.

  Since this is still nominally a multimedia blog, I’ll start of the screenshot recon with an old multimedia player. Here is a vintage Mac OS desktop running an ancient web browser (probably Netscape) that’s playing a full-window video (probably QuickTime embedded directly into the browser).

  
  

  

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  Let’s jump right into the Linux side of things. This screenshot makes me particularly sentimental since this is exactly what a stock Linux/KDE desktop looked like circa 2001-2003 and is more or less what I would have worked with on my home computer at the time :

  
  

  

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  Studying that screenshot, we see that the user logs in as root, even to the desktop environment. Poor security practice ; I would expect better from a bunch of spooks.

  Echelon
  Look at the terminal output in the above screenshot– it’s building a program named Echelon, an omniscient spy tool inspired by a real-world surveillance network of the same name. In the show, Echelon is used to supply plot-convenient intelligence. At one point, some antagonists get their hands on the Echelon source code and seek to compile it. When they do, they will have access to the vast surveillance network. If you know anything about how computers work, don’t think about that too hard.

  Anyway, it’s interesting to note that Echelon is a properly autotool’d program– when the bad guys finally got Echelon, installation was just a ‘make install’ command away. The compilation was very user-friendly, though, as it would pop up a nice dialog box showing build progress :

  
  

  

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  Examining the build lines in both that screenshot and the following lines, we can see that Echelon cares about files such as common/db_err.c and bt_curadj.c :

  
  

  

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  A little googling reveals that these files both belong to the Berkeley DB library. That works ; I can imagine a program like this leveraging various database packages.

  Computer Languages
  The Echelon source code stuff comes from episode 2.11 : “A Higher Echelon”. While one faction had gotten a hold of the actual Echelon source code, a rival faction had abducted the show’s resident uber-nerd and, learning that they didn’t actually receive the Echelon code, force the nerd to re-write Echelon from scratch. Which he then proceeds to do…

  
  

  

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  The code he’s examining there appears to be C code that has something to do with joystick programming (JS_X_0, JS_Y_1, etc.). An eagle-eyed IMDb user contributed the trivia that he is looking at the file /usr/include/Linux/joystick.h.

  Getting back to the plot, how could the bad buys possibly expect him to re-write a hugely complex piece of software from scratch ? You might think this is the height of absurdity for a computer-oriented story. You’ll be pleased to know that the writers agreed with that assessment since, when the program was actually executed, it claimed to be Echelon, but that broke into a game of Pong (or some simple game). Suddenly, it makes perfect sense why the guy was looking at the joystick header file.

  This is the first bit of computer-oriented fun that I captured when I was watching the series :

  
  

  

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  This printout purports to be a “mainframe log summary”. After some plot-advancing text about a security issue, it proceeds to dump out some Java source code.

  SSH
  Secure Shell (SSH) frequently showed up. Here’s a screenshot in which a verbose ‘ssh -v’ connection has just been closed, while a telnet command has apparently just been launched (evidenced by “Escape character is ‘^]’.”) :

  
  

  

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  This is followed by some good old Hollywood Hacking in which a free-form database command is entered through any available command line interface :

  
  

  

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  I don’t remember the episode details, but I’m pretty sure the output made perfect sense to the character typing the command. Here’s another screenshot where the SSH client pops up an extra-large GUI dialog element to notify the user that it’s currently negotiating with the host :

  
  

  

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  Now that I look at that screenshot a little more closely, it appears to be a Win95/98 program. I wonder if there was an SSH client that actually popped up that gaudy dialog.

  There’s a lot of gibberish in this screenshot and I wish I had written down some details about what it represented according to the episode’s plot :

  
  

  

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  It almost sounds like they were trying to break into a network computer. Analyzing MD5 structure… public key synthesized. To me, the funniest feature is the 7-digit public key. I’m a bit rusty on the math of the RSA cryptosystem, but intuitively, it seems that the public and private keys need to be of roughly equal lengths. I.e., the private key in this scenario would also be 7 digits long.

  Gadgets
  Various devices and gadgets were seen at various junctures in the show. Here’s a tablet computer from back when tablet computers seemed like fantastical (albeit stylus-requiring) devices– the Fujitsu Stylistic 2300 :

  
  

  

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  Here’s a videophone from an episode that aired in 2005. The specific model is the Packet8 DV326 (MSRP of US$500). As you can see from the screenshot, it can do 384 kbps both down and up.

  
  

  

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  I really regret not writing down the episode details surrounding this gadget. I just know that it was critical that the good guys get it and keep from falling into the hands of the bad guys.

  
  

  

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  As you can see, the (presumably) deadly device contains a Samsung chip and a Lexar chip. I have to wonder what device the production crew salvaged this from (probably just an old cell phone).

  Other Programs

  The GIMP photo editor makes an appearance while scrubbing security camera footage, and serves as the magical Enhance Button (at least they slung around the term “gamma”) :

  
  

  

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  I have no idea what MacOS-based audio editing program this is. Any ideas ?

  
  

  

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  FTP shows up in episode 2.12, “The Getaway”. It’s described as a “secure channel” for communication, which is quite humorous to anyone versed in internet technology.

  
  

  

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• Impossible to redirect video stream after conversion (mkv to mp4)

  17 décembre 2019, par elgrusko

  I’m currently realising a school project which aims a streaming video website (like Netflix) using torrent-stream (with the magnet link). I am using NodeJS for the stream part.

  My problem is : I can’t redirect the stream to the HTML 5 player while i’m trying to stream and converting (with ffmpeg) video at the same time. I think it’s because I just can’t know what’s will be the final size of the converted file.
  In browser’s console I have this message : net::ERR_CONTENT_LENGTH_MISMATCH 200 (OK)

  I tried to put this in the header : Transfer-Encoding: chunked instead of Content-Length
  I specify that the stream (before conversion) works perfectly

  This is my code :

  getTorrentFile.then(function (file) {
  
                  res.setHeader('Content-Type', 'video/mp4');
  
                  res.setHeader('Content-Length', file.length);
  
                  const ranges = parseRange(file.length, '15' /* variable à comprendre */, { combine: true });
  
                  console.log(ranges);
  
                  if (ranges === -1) {
  
                      // 416 Requested Range Not Satisfiable
  
                      console.log('416')
  
                      res.statusCode = 416;
  
                      return res.end();
  
                  } else if (ranges === -2 || ranges.type !== 'bytes' || ranges.length > 1) {
  
                      // 200 OK requested range malformed or multiple ranges requested, stream ent'ire video
  
                      if (req.method !== 'GET') return res.end();
  
                      console.log('200')
  
                      stream = file.createReadStream()
  
                      ffmpeg(stream)
  
                      .videoCodec('libx264')
  
                      .audioCodec('aac')
  
                      .output(res)
  
                      .output('./video/' + film + '_s' + season + '_e' + episode + '.mp4')
  
                      .outputFormat('mp4')
  
                      .outputOptions('-movflags frag_keyframe+empty_moov')
  
                      .on('error', function(err) {
  
                          console.log('An error occurred: ' + err.message);
  
                      })
  
                      .on('progress', function(progress) {
  
                          console.log('Processing: ' + progress.targetSize + 'kb done');
  
                        })
  
                      .on('end', function() {
  
                          console.log('Processing finished !');
  
                      })
  
                      .addOutputOption('-acodec')
  
                      .run()

  Sorry if i’m not really clear, ask me some questions if you need more informations :)

  Thanks for your help, bye :)

• Bash script to automate FFmpeg operations fails when calling the command, but copy-pasting the generated command into the terminal works [duplicate]

  28 février, par GaboScharff99

  I wrote a bash script which automates a number of conversion operations on video files using FFmpeg. Oddly enough, the FFmpeg call itself now fails when running the script, with a very confusing error message, I might add, but when I copy the command generated by the script into the terminal and run it, it works flawlessly. I'm sorry to insert such a long code block here, but considering how strange this error is, it might be anywhere in the script, so here it is :

  


  #!/bin/bash

audioTrack=1
subSource=1
subTrack=0
transcodeVideo=1
transcodeAudio=1
volumeMultiplier=1
degradeToStereo=0
subLanguage="Japanese"

while getopts "t:ns:vam:dl:h" opt; do
    case "$opt" in
        t) audioTrack=${OPTARG};;
        n) subSource=0;;
        s) subTrack=${OPTARG};;
        v) transcodeVideo=0;;
        a) transcodeAudio=0;;
        m) volumeMultiplier=${OPTARG};;
        d) degradeToStereo=1;;
        l) subLanguage=${OPTARG};;
        h)
            echo "Options:"
            echo "-t [integer]: Audio track number. Default: 1."
            echo "-n: If included, subtitles will be taken from internal source."
            echo "-s [integer]: Subtitles track number. Default: 0."
            echo "-v: If included, video source will be copied without transcoding."
            echo "-a: If included, audio source will be copied without transcoding."
            echo "-m [number]: Volume multiplier. If 1, volume is unaffected. Default: 1"
            echo "-d: If included, audio will be degraded to stereo."
            echo "-l [language]: Subtitles language. Only used for external subtitles source. Default: Japanese."
            exit 0
        ;;
    esac
done

echo "Audio track: $audioTrack."
echo "Subtitles track: $subTrack."
params="-map 0:0 -map 0:$audioTrack -map $subSource:$subTrack -c:v"

if [[ $transcodeVideo -eq 1 ]]; then
    echo "Video will be transcoded."
    params="$params hevc"
elif [[ $transcodeVideo -eq 0 ]]; then
    echo "Video will be copied without transcoding."
    params="$params copy"
fi

params="$params -c:a"

if [[ $transcodeAudio -eq 1 ]]; then
    echo "Audio will be transcoded."
    params="$params libopus"
elif [[ $transcodeAudio -eq 0 ]]; then
    echo "Audio will be copied without transcoding."
    params="$params copy"
fi

if [[ $volumeMultiplier -ne 1 ]]; then
    echo "Volume will be multiplied by a factor of $volumeMultiplier."
    params="$params -filter:a 'volume=$volumeMultiplier'"
else
    echo "Volume will be unaffected."
fi

if [[ $degradeToStereo -eq 1 ]]; then
    echo "Audio will be degraded to stereo."
    params="$params -ac 2"
elif [[ $degradeToStereo -eq 0 ]]; then
    echo "Audio will not be degraded to stereo."
fi

params="$params -c:s copy"

if [[ $subSource -eq 1 ]]; then
    echo "Subtitles source is external."
    echo "Subtitles language is $subLanguage."
    params="$params -metadata:s:s:0 title='' -metadata:s:s:0 language='$subLanguage'"
else
    echo "Subtitles source is internal."
fi

if [[ -f titles.txt ]]; then
    echo "A titles.txt file was found. Titles will be changed according to it."
    echo "Please check titles.txt to make sure the titles are correct."
    changeTitles=1
    counter=0
else
    echo "A titles.txt file was not found. Titles will not be changed."
    changeTitles=0
fi

read -p "Are these options correct? (y/n) " choice

case "$choice" in
    y|Y)
        echo "Initiating conversion sequence. This may take a while..."

        mkdir output
        currentParams=""

        shopt -s nullglob
        for i in *.mp4 *.mkv; do
            currentParams=$params
            fileNameNoExtension=$(echo $i | rev | cut -f 2- -d '.' | rev)

            if [[ $subSource -eq 1 ]]; then
                currentParams="-f srt -i $fileNameNoExtension.srt $currentParams"
            fi

            if [[ $changeTitles -eq 1 ]]; then
                ((counter++))
                currentParams="$currentParams -metadata title='$(awk "NR==$counter" titles.txt)'"
            fi

            ffmpeg -i "$i" $currentParams "output/$fileNameNoExtension.mkv"
        done

        echo "Conversion finished!"
    ;;
    n|N) echo "Operation canceled. Exiting.";;
    *) echo "Invalid input. Try again.";;
esac


  


  The directory I'm running this in contains six video files :

  


  

  1. E1 - The Pirates of Orion.mkv

  


  2. E2 - Bem.mkv

  


  3. E3 - The Practical Joker.mkv

  


  4. E4 - Albatross.mkv

  


  5. E5 - How Sharper Than a Serpent's Tooth.mkv

  


  6. E6 - The Counter-Clock Incident.mkv

  


  


  Here's the titles.txt file, for completion's sake :

  


  Star Trek: The Animated Series - Season 2, Episode 1 - The Pirates of Orion
Star Trek: The Animated Series - Season 2, Episode 2 - Bem
Star Trek: The Animated Series - Season 2, Episode 3 - The Practical Joker
Star Trek: The Animated Series - Season 2, Episode 4 - Albatross
Star Trek: The Animated Series - Season 2, Episode 5 - How Sharper Than a Serpent's Tooth
Star Trek: The Animated Series - Season 2, Episode 6 - The Counter-Clock Incident


  


  And finally, here's the error message given by FFmpeg on the terminal for every video file when running the command :

  


  Unable to find a suitable output format for 'Trek:'
Trek:: Invalid argument


  


  Maybe there are better ways to handle all of this, but first and foremost, I would like to figure out why the command fails with such a confusing error message. The only place where the string 'Trek :' is found is in the title taken from titles.txt, but I don't understand why that's seemingly being passed to the name of the output file instead of the title, and apparently only when running the script.

  


  Thanks a lot for your answers ! I know this is quite a bit of text, so I really appreciate you taking your time to read through this.